This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Fractal dimension has been used to quantify the structures of a wide range of objects in biology and medicine. In this study we will measure the fractal dimension (FD) of human cerebellum (CB) using MR CB images. High resolution coronal MRI brain images covering the whole CB will be collected from healthy adult subjects and patients with white matter diseases (AUTISM, MS, etc.) CB images will be resampled to a series of image sets with different three-dimensional resolutions. At each resolution, the skeleton of the CB white matter will be obtained and the number of pixels belonging to the skeleton will be determined. Fractal dimension of the CB skeleton will be calculated using the box-counting method. Fractal dimension will be compared between the normal subjects group and patients group to quantify the structure changes. The fractal dimension may serve as a quantitative index for structural complexity and morphometric changes of the CB at its developmental, degenerative, diseased or evolutional stages.